CN114128412A

CN114128412A - Circuit structure, electrical connection box, and method for manufacturing circuit structure

Info

Publication number: CN114128412A
Application number: CN202080008184.XA
Authority: CN
Inventors: 土田敏之
Original assignee: Sumitomo Wiring Systems Ltd; AutoNetworks Technologies Ltd; Sumitomo Electric Industries Ltd
Current assignee: Sumitomo Wiring Systems Ltd; AutoNetworks Technologies Ltd; Sumitomo Electric Industries Ltd
Priority date: 2019-01-24
Filing date: 2020-01-14
Publication date: 2022-03-01
Also published as: WO2020153164A1; US20220130584A1; JP2020120003A

Abstract

A circuit structure (20) is provided with: a circuit board (21) in which a conductive path and a through hole (22) electrically connected to the conductive path are formed; a coil device (50) provided with a coil (51) and a core (54) of a magnet, the coil (51) having a terminal section (52); a heat radiation member (30) having a housing recess (34) for housing a coil device (50), and on which a circuit board (21) is superimposed; and grease (25) which is in contact with the inner surface of the housing recess (34) and the coil device (50), and the terminal section (52) of the coil device (50) is inserted through the through hole (22) and soldered.

Description

Circuit structure, electrical connection box, and method for manufacturing circuit structure

Technical Field

The technology described in the present specification relates to a circuit structure and an electrical junction box.

Background

A vehicle such as an automobile is equipped with an electrical junction box such as a DC-DC converter, and a coil is used as a circuit element of the electrical junction box. In the electrical junction box of patent document 1, a frame-shaped member made of synthetic resin is covered on an outer peripheral portion of a heat radiating member, a circuit board is housed in the frame-shaped member, and a choke coil is arranged in a divided portion of the frame-shaped member.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2014-103747

Disclosure of Invention

Problems to be solved by the invention

However, since other electronic components cannot be mounted on the region where the coil is disposed on the heat dissipating member, it is necessary to secure a region for mounting other electronic components in the electrical junction box, and it is not easy to miniaturize the electrical junction box. In particular, if a coil capable of conducting a large current is mounted on the electrical connection box, the coil becomes large, and thus the area occupied by the coil increases, which causes a problem that the electrical connection box tends to become large.

The technology described in the present specification is an invention based on the above-described situation, and an object thereof is to miniaturize a circuit structure and an electrical junction box.

Means for solving the problems

The circuit structure described in this specification includes: a circuit board formed with a conductive via and a through hole electrically connected to the conductive via; a coil device including a coil and a core of a magnet, the coil having a terminal portion; a heat radiation member having a housing recess housing the coil device and on which the circuit board is superposed; grease is in contact with the inner surface of the housing recess and the coil device, and the terminal portion of the coil device is inserted through the through hole and soldered thereto.

In the method for manufacturing a circuit structure described in the present specification, a coil device having a core of a coil and a magnet is accommodated in an accommodating recess portion of a heat dissipating member in which the accommodating recess portion is formed, with grease being disposed in the accommodating recess portion, the coil device is brought into contact with the grease, and a terminal portion of the coil is soldered by being inserted through a through hole of a circuit board in which a conductive path and a through hole electrically connected to the conductive path are formed.

According to the above configuration, since the coil device is accommodated in the accommodating recess of the heat radiation member and the grease is in contact with the coil device and the inner surface of the accommodating recess of the heat radiation member, the coil device can be positioned in the accommodating recess by the grease and the heat of the coil device can be transmitted to the heat radiation member via the grease. Thus, it is not necessary to provide a structure for fixing the coil device outside the housing recess, and therefore, the area outside the housing recess where other elements can be mounted can be increased. This can improve the mounting density of elements in the circuit structure, and can reduce the size of the circuit structure.

As embodiments of the technology described in the present specification, the following embodiments are preferred.

The grease used was a normal temperature curing type grease.

In this case, since it is not necessary to perform an operation for solidifying the grease, the manufacturing process can be simplified.

The housing recess has a bottom surface portion and an inner wall portion rising from the bottom surface portion, and the grease is disposed on the bottom surface portion side of the housing recess.

In this case, the coil device can be easily accommodated in the accommodating recess.

The grease is disposed between the inner surface of the housing recess and the coil device, and is also disposed between the circuit board and the heat dissipating member outside the housing recess.

In this case, when the grease is applied to the inside of the accommodating recess, the grease for adhesion, insulation, and the like between the circuit board and the heat dissipating member can be applied, and therefore, the manufacturing process can be simplified.

The coil is a flat coil wound such that a short side of a flat wire becomes an inner diameter surface, and is wound around an axis passing through a plane along a surface of the heat dissipating member on the circuit substrate side.

In this case, the circuit structure can be easily miniaturized by the orientation of the coil device.

The circuit board is fastened to the heat dissipation member with a screw thread in a state of being spaced apart from the heat dissipation member.

In this case, the element can be mounted at the space between the circuit board and the heat dissipating member, and the circuit board can be firmly fixed to the heat dissipating member by the screw.

An electrical connection box is provided with the circuit structure and a cover for covering the circuit structure.

Effects of the invention

According to the technology described in the present specification, the circuit structure and the electrical junction box can be miniaturized.

Drawings

Fig. 1 is a sectional view showing an electrical junction box according to embodiment 1.

Fig. 2 is a perspective view showing a circuit structure.

Fig. 3 is a sectional view of the circuit structure.

Fig. 4 is a perspective view showing the circuit board.

Fig. 5 is a perspective view showing the heat dissipating member.

Fig. 6 is a perspective view showing a state where grease is applied to the upper surface of the heat radiating member.

Fig. 7 is a plan view showing a state where grease is applied to the upper surface of the heat radiating member.

Fig. 8 is a sectional view a-a of fig. 7.

Fig. 9 is a perspective view showing a state in which the coil device is accommodated in the accommodating recess from the state of fig. 7.

Fig. 10 is a plan view showing a state where the coil device is accommodated in the accommodating recess portion from the state of fig. 7.

Fig. 11 is a sectional view B-B of fig. 10.

Fig. 12 is a perspective view showing a state in which the circuit board is mounted on the heat dissipating member from the state of fig. 10.

Fig. 13 is a sectional view showing an electrical junction box according to embodiment 2.

Fig. 14 is a perspective view showing a circuit structure.

Fig. 15 is a sectional view of the circuit structure body.

Fig. 16 is a perspective view showing a heat dissipating member.

Fig. 17 is a sectional view showing a state in which the coil device is mounted on grease in the housing recess.

Fig. 18 is a perspective view showing a state in which the circuit board is mounted on the boss portion of the heat radiation member from the state of fig. 17.

Fig. 19 is a perspective view showing a state where the circuit board and the boss portion of the heat radiating member are screwed from the state of fig. 18.

Detailed Description

< embodiment 1>

The electrical connection box 10 according to embodiment 1 will be described with reference to fig. 1 to 12.

The electrical junction box 10 of the present embodiment is disposed in a power supply path between a power source such as a battery of a vehicle such as an electric vehicle or a hybrid vehicle and a load including a lamp, a vehicle-mounted electrical component such as a wiper, a motor, and the like, and can be used in, for example, a DC-DC converter, an inverter, and the like. Hereinafter, the X direction in fig. 1 is the left direction, the Z direction is the upper direction, and the Y direction in fig. 2 is the front direction.

As shown in fig. 1, the electrical junction box 10 includes a circuit structure 20 and a cover 11 covering the circuit structure 20. The cover 11 is made of metal or synthetic resin, has a box shape with a lower side opened, and is fixed to the heat radiating member 30 by screwing with screws 12.

As shown in fig. 3, the circuit structure 20 includes: a circuit board 21; a heat radiation member 30 for radiating heat of the circuit board 21 and the coil device 50; grease 25 superposed on the upper surface of the heat radiation member 30; and a coil device 50 housed in the housing recess 34 of the heat radiation member 30.

The circuit board 21 is a printed board in which a conductive path made of copper foil is formed on an insulating plate made of an insulating material by a printed wiring technique, and electronic components not shown are mounted on the conductive path of the circuit board 21. As shown in fig. 4, a plurality of oblong through holes 22 penetrating through the insulating plate are formed in the circuit board 21 at positions connected to the conductive paths. A copper foil is provided on the entire inner surface of the through hole 22 and connected to a conductive path on the upper surface of the circuit board 21. The circuit board 21 is a printed board, but is not limited to this, and for example, a busbar made of a metal plate material may be stacked on the printed board to form a circuit board. As shown in fig. 1, the circuit board 21 is disposed on the grease 25 applied to the mounting surface 32 of the heat dissipation member 30, and is in close contact with the mounting surface 32 via the grease 25.

(Heat radiating member 30)

The heat radiation member 30 is made of metal having high thermal conductivity, such as aluminum or aluminum alloy formed of cast aluminum, for example, and includes a main body 31 on which the circuit board 21 is mounted, and a plurality of heat radiation fins 49 connected to a lower portion of the main body 31 and arranged in a comb shape, as shown in fig. 5.

A cutout 31A is formed on the front side of the main body 31, and a connector, not shown, having a terminal connected to the circuit board 21 is disposed in the cutout 31A. The upper surface of the main body 31 is a mounting surface 32 on which the circuit board 21 is mounted in a state in which the grease 25 is laminated.

A housing recess 34 for housing the coil device 50 is formed in the mounting surface 32. As shown in fig. 7 and 8, the housing recess 34 includes: a bottom surface portion 35 having a rectangular shape elongated in the front-rear direction; and an inner wall portion 36 that rises from the periphery of the bottom surface portion 35 and faces the outer surface of the coil device 50 to surround the coil device 50, and a substantially rectangular parallelepiped space is formed in the heat radiation member 30.

A mounting portion 42 to which the cover 11 can be mounted is provided on the outer periphery of the main body 31. The mounting portion 42 has a screw hole 42A formed therethrough. The mounting portion 42 can connect the heat radiation member 30 to the ground potential by being fixed to the vehicle body or the like, for example.

As shown in fig. 7 and 8, the grease 25 includes a first grease 25A stacked on the bottom surface portion 35 of the housing recess 34 with a predetermined thickness and a second grease 25B stacked on the mounting surface 32 with a predetermined thickness. In the present embodiment, the thicknesses of the first grease 25A and the second grease 25B are substantially the same, but the thicknesses of the first grease 25A and the second grease 25B may be different, and for example, the thickness of the first grease 25A may be thicker than the thickness of the second grease 25B. The grease 25 is a grease in which a thickener is dispersed in a lubricating oil to form a semisolid or solid state, and a material having high thermal conductivity and insulation properties is used, and for example, silicone grease, fluoroether grease, or the like can be used. The grease 25 is preferably set to have a viscosity such that the position of the coil device 50 placed on the grease 25 can be held. The grease 25 is preferably a grease having a higher viscosity than a liquid adhesive (an adhesive before curing), and is preferably a grease cured at room temperature. For example, a biliquid of a biliquid silicone heat-dissipating grease that is curable at room temperature (e.g., 25 ℃) (e.g., within a few hours) may be mixed. Furthermore, a sticky grease with increased tack by adding additives may also be used.

The coil device 50 is, for example, a choke coil for smoothing an output voltage, and includes, as shown in fig. 3, a pair of coils 51 (only one of which is shown in fig. 3), a core 54 of a magnet, and a bobbin 60 for holding the coils 51 in the core 54. Each coil 51 is a so-called flat coil, and is formed by spirally winding a strip-shaped flat wire made of, for example, copper or a copper alloy and having a flat rectangular cross section so that the short sides thereof become the inner diameter surface and the outer diameter surface, and the outer surface thereof is covered with a varnish. Each coil 51 has a pair of terminal portions 52, and the pair of terminal portions 52 extend in a tangential direction at terminal portions of a winding portion formed by winding a plurality of turns around an axial center in a circular shape and are connected to the outside. The pair of terminal portions 52 are both arranged linearly and in parallel to each other. The extending direction of the pair of terminal portions 52 is perpendicular to the placement surface 32 of the heat sink member 30.

The core 54 is formed of a magnetic body having high permeability such as ferrite, and is formed by combining a pair of

split bodies

55A and 55B. Each of the paired split

bodies

55A and 55B includes a pair of columnar column portions inserted into the coil 51, a plate-shaped coupling portion coupling the pair of column portions, and a partition wall disposed between the pair of column portions to partition the pair of coils 51, and these are formed integrally. The bobbin 60 is made of an insulating synthetic resin, is configured by combining a pair of divided

members

61A and 61B, and has a cylindrical tube portion through which the pillar portion of the core 54 is inserted, and holds the position of the coil 51 in the core 54.

Next, the assembly of the coil device 50 will be explained.

The coil device 50 is formed by disposing the coil 51 between the pair of divided

members

61A, 61B and assembling the pair of

split bodies

55A, 55B.

Next, as shown in fig. 6 and 7, grease 25 is applied to the upper surface (the bottom surface portion 35 and the mounting surface 32) of the heat radiating member 30. Next, as shown in fig. 9 and 10, the coil device 50 is inserted into the receiving recess 34 of the heat dissipating member 30 in a posture in which all the terminal portions 52 of the coil device 50 face upward. When the coil device 50 is inserted to a predetermined depth in the housing recess 34, the coil device 50 is placed on the grease 25A (fig. 11).

Next, as shown in fig. 12, the circuit board 21 is disposed above the heat radiating member 30, the terminal portion 52 of the coil device 50 is inserted into the through hole 22 of the circuit board 21, and the circuit board 21 is placed on the grease 25B of the placement surface 32. Next, the terminal portion 52 is soldered to the through hole 22 of the circuit board 21 with the solder S to form the circuit structure 20 (fig. 2). Then, when the cover 11 is attached to the circuit structure 20 by screwing the screws 12, the electrical connection box 10 (fig. 1) is formed.

According to the present embodiment, the following operation and effects are exhibited.

The circuit structure 20 includes: a circuit board 21 having a conductive path and a through hole 22 electrically connected to the conductive path; a coil device 50 including a coil 51 and a core 54 of a magnetic body, the coil 51 having a terminal portion 52; a heat radiation member 30 having a housing recess 34 for housing the coil device 50, and the circuit board 21 being superposed on the heat radiation member 30; and grease 25 in contact with the inner surface of the housing recess 34 and the coil device 50, and the terminal portion 52 of the coil device 50 is inserted through the through hole 22 and soldered.

According to the present embodiment, since the coil device 50 is housed in the housing recess 34 of the heat radiating member 30 and the grease 25 is in contact with the coil device 50 and the inner surface of the housing recess 34 of the heat radiating member 30, the coil device 50 in the housing recess 34 can be positioned by the grease 25 and the heat of the coil device 50 can be transmitted to the heat radiating member 30 via the grease 25. Accordingly, it is not necessary to provide a structure for fixing the coil device 50 outside the housing recess 34, and therefore, the area outside the housing recess 34 where other components can be mounted can be increased. This can increase the density of mounting elements in the circuit structure 20, and can reduce the size of the circuit structure 20.

In the manufacture of circuit structure 20, circuit board 21 and heat dissipation member 30 may be superposed on each other and terminal portion 52 may be inserted into through-hole 22 before soldering. Thus, for example, compared to a configuration in which an adhesive is used without using grease, the work of assembling the circuit board 21 can be performed without waiting for curing of the adhesive after the coil device 50 is accommodated in the accommodating recess 34, and thus the manufacturing process can be simplified.

As the grease 25, a normal temperature curing type grease was used.

In this case, since the work for curing the grease 25 is not necessary, the manufacturing process can be simplified. Further, during manufacturing, the stress applied to the circuit board 21 and the like can be reduced by the flexibility of the grease.

The housing recess 34 has a bottom surface 35 and an inner wall 36 rising from the bottom surface 35, and the grease 25 is disposed on the bottom surface 35 side of the housing recess 34.

In this way, the coil device 50 can be easily accommodated in the accommodating recess 34.

The grease 25 is disposed between the inner surface of the accommodating recess 34 and the coil device 50, and also between the circuit board 21 outside the accommodating recess 34 and the heat radiating member 30.

In this way, when the grease 25 is applied to the inside of the accommodating recess 34, the grease 25 for adhesion, insulation, and the like between the circuit board 21 and the heat radiating member 30 can be applied to the mounting surface 32 of the heat radiating member 30, and therefore, the manufacturing process can be simplified.

The coil 51 is a flat coil wound such that the short side of the flat wire is the inner diameter surface, and is wound around an axis passing through the surface of the heat radiating member 30 on the circuit board 21 side.

In this case, the circuit structure 20 can be easily miniaturized by the orientation of the coil device 50.

< embodiment 2>

Next, embodiment 2 will be described with reference to fig. 13 to 19. Embodiment 2 is a structure in which the circuit board 72 is screwed to the boss portion 76 of the heat radiation member 75 by a screw 79. Hereinafter, the same components as those in embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

As shown in fig. 13, the electrical connection box 70 includes a circuit structure 71 and a cover 11 covering the circuit structure 71. The circuit structure 71 includes a circuit board 72, a heat dissipating member 75 for dissipating heat from the circuit board 72 and the coil device 50, and the coil device 50 accommodated in the accommodating recess 34 of the heat dissipating member 75.

As shown in fig. 18, a plurality of (4 in the present embodiment) through holes 73 are formed through each corner of the rectangular circuit board 72, and the shaft of the screw 79 is inserted into the through holes 73 at the time of screwing. As shown in fig. 16, a plurality of (4 in the present embodiment) boss portions 76 are formed on the upper surface 75A of the heat radiating member 75 at positions corresponding to the through holes 73 of the circuit board 72. The boss portion 76 has a columnar shape and protrudes upward (in the axial direction) at a predetermined height with respect to the upper surface 75A. The boss portion 76 is formed with a screw hole 77 for screwing the shaft portion of the screw 79. Although grease can be applied to the upper surface of the boss portion 76 and the region of the upper surface 75A of the heat radiation member 75 outside the housing recess 34, grease may not be applied. As shown in fig. 15, grease 74 is disposed at a predetermined thickness on the bottom surface portion 35 of the housing recess 34, and the grease 74 is in contact with the coil device 50 and the bottom surface portion 35. The grease 74 may be the same grease as the grease 25 of embodiment 1.

Next, the assembly of the coil device 50 will be explained.

The coil device 50 is formed by arranging the coil 51 between the pair of

split members

61A, 61B and assembling the pair of

split bodies

55A, 55B.

Further, the grease 25 is applied to the bottom surface portion 35 of the receiving recess 34 of the heat radiation member 75 in a predetermined thickness. Next, the coil device 50 is inserted into the receiving recess 34 of the heat dissipating member 75 in a posture in which all the terminal portions 52 of the coil device 50 face upward. When the coil device 50 is inserted to a predetermined depth into the housing recess 34, the coil device 50 is placed on the grease 25 as shown in fig. 17.

Next, the circuit board 72 is disposed above the heat dissipating member 75, and the terminal portion 52 of the coil device 50 is inserted into the through hole 22 of the circuit board 72. At this time, for example, as shown in fig. 17, when the upper surface of the coil device 50 is located above the upper surface of the boss portion 76, the upper end portion of the coil device 50 may be pressed downward by the circuit board 72 to embed the lower end portion of the coil device 50 in the grease 25. After the circuit board 72 is placed on the boss portion 76, the shaft portion of the screw 79 is screwed to the boss portion 76 through the through hole 73 of the circuit board 72. Next, terminal portion 52 is soldered to through hole 22 of circuit board 72 with solder S, thereby forming circuit structure 71 (fig. 14). When the cover 11 is attached to the circuit structure 71 by screwing the screws 12, an electrical connection box 70 is formed (fig. 13).

According to embodiment 2, since the circuit board 72 is screwed to the heat dissipation member 75 by the screw 79 in a state where the circuit board is spaced apart from the heat dissipation member 75, the component can be mounted on the space between the circuit board 72 and the heat dissipation member 75, and the circuit board 72 can be firmly fixed to the heat dissipation member 75 by the screw 79.

< other embodiment >

The technology described in the present specification is not limited to the embodiments described above and illustrated in the drawings, and for example, the following embodiments are also included in the technical scope of the technology described in the present specification.

(1) The grease 25, 74 is disposed on the bottom surface portion 35 side of the housing recess 34, but is not limited thereto. For example, the grease 25, 74 may be disposed on the inner wall portion 36 side of the housing recess 34.

(2) The grease 25 is disposed not only between the inner surface of the accommodating recess 34 and the coil device 50 but also between the circuit board 21 outside the accommodating recess 34 and the heat radiating member 30. For example, an adhesive may be disposed between the circuit board 21 and the heat dissipation member 30 instead of the grease 25.

(3) The coil 51 is a flat coil, but is not limited thereto. For example, a coil having a circular cross section may be used.

(4) The coil device 50 is provided as a coupling coil having two coils 51, but is not limited thereto. For example, the coil device may have a structure having one coil. The coil device 50 is a choke coil, but is not limited to this, and may be used for other applications.

(5) The number of turns of the coil 51 is not limited to the above embodiment, and may be different.

(6) The coil device 50 is configured to include the bobbin 60, but is not limited to this, and may be configured not to include the bobbin 60.

Description of the reference symbols

10. 70: electric connection box

11: cover

20. 71: circuit structure

21. 72: circuit board

22: through hole

25. 74: lubricating grease

30. 75: heat radiation component

32: carrying surface

34: accommodating recess

35: bottom surface part

36: inner wall part

50: coil device

51: coil

52: terminal section

54: core

73: through hole

76: boss part

77: threaded hole

79: screw nail

S: and (3) soldering.

Claims

1. A circuit structure body is provided with:

a circuit board formed with a conductive via and a through hole electrically connected to the conductive via;

a coil device including a coil and a core of a magnet, the coil having a terminal portion;

a heat radiation member having a housing recess housing the coil device and on which the circuit board is superposed; and

grease which is in contact with the inner surface of the housing recess and the coil device,

the terminal portion of the coil device is inserted through the through hole and soldered thereto.

2. The circuit structure body according to claim 1,

the grease used was a normal temperature curing type grease.

3. The circuit structure body according to claim 1 or 2,

the housing recess has a bottom surface portion and an inner wall portion rising from the bottom surface portion,

the grease is disposed on the bottom surface side in the housing recess.

4. The circuit structure according to any one of claims 1 to 3,

5. The circuit structure according to any one of claims 1 to 4,

6. The circuit structure according to any one of claims 1 to 5,

7. An electrical connection box comprising the circuit structure according to any one of claims 1 to 6 and a cover covering the circuit structure.

8. A method for manufacturing a circuit structure, wherein,

a coil device having a core of a coil and a magnet is accommodated in an accommodating recess portion of a heat dissipating member in which the accommodating recess portion is formed, with grease being disposed in the accommodating recess portion, and the coil device is brought into contact with the grease, and a terminal portion of the coil is soldered by being inserted through a through hole of a circuit board in which a conductive path and a through hole electrically connected to the conductive path are formed.